PeterH

This looks like the manual https://kilns.pro/wp-content/uploads/2023/01/PC3L-User-Manual.pdf

An item on Amazon looks similar and has some stats. https://www.amazon.co.uk/Top-Loaded-programmable-Pottery-Projects-Beginners/dp/B0BZ53RXKM ... it includes

Your not alone there. White is just about the first adjective I think of when bone china is mentioned. It's an interesting idea that it might really be objectively bluish but subjectively "whiter than white" (like many detergents). The change from "whiter than white" to a more visible greenish tint then doesn't seem so implausible. Possibly due to some subtle change in the nature of the glass in which the (iron?) chromophore is embedded. From @Min's reference. PS a test-tile without Veegum seems an increasingly interesting idea. BTW how are small test-tiles for different body compositions usually made? Using volumetric mixing ideas from glaze tests would seem sensible if you need to do lots. Perhaps drying the over-wet samples on plaster or in plaster moulds - or applying as a slip to a biscuit tile (although that might make inspection more difficult). PPS Can you confirm that you have observed the green tint under several different lighting conditions. So we can exclude any light-spectrum related issues (c.f. neodymium glass).

Some plausible-looking advice on techniques and H&S referenced in: Historically there have been two sorts of lustres: reduction lustres and resinate lustres. Your comments seem to apply more to the reduction-fired reduction lustres. While tho commercial oxidation fired products are resinate lustres. Ever wondered why solder is often sold with a rosin flux running through it? When you apply it to the joint the hot rosin reacts with any oxide on the copper surfaces to form copper resinate. The resinates lustres are made by reacting metal oxides or salts with rosin and dissolving the resinate in or another solvent. With luck you finish up with quite a high concentration of metal resinate in the solvent. When these are fired they decompose leaving a thin metal film (and often some pretty nasty fumes). As Min said, do try and get in touch with @liambesaw if you can, but he hasn't visited the here since 2022. A friend used to run a garage industry making resinates and had very strong reservations about many of the solvents used in commercial lustres, sticking to - AFAIK - linseed oil. Manufacture a gold lustre is fairly briefly covered in "Pottery Decorating" by R. Hainbach. Which involves mixing "bright gold" with a bismuth lustre. Bright gold apparently containing resinates of gold and rhodium (and also possibly bismuth, uranium, chromium and iron?). Although a simpler wet process is also described for producing gold resinate from gold trichloride and resin-soap. ... probably much better to find out what people do nowadays. PS The book seems fairly expensive at the moment, change this search to your location and currency. https://tinyurl.com/2d783cv8

I meant a something like a normal bisque temperature, rather than the high-bisque used for bone china. In a hand-waving sense the more refractory ingredients wouldn't have entered the melt at that stage. OTOH the bisque nature of the test-tile might impede looking for the colour.

Any idea of the likely source? Or the likely level of contamination?

Starting a new thread with an eye-catching title such as "Why is my bone-china green?" would probably draw a wider audience. In desperation: - I cannot see how it could be a kiln issue, but can you get somebody else to fire a test-tile for you? - It also would be interesting to see how a low-fired test-tile came out.

Just to point out that your approximation does not allow for the volume occupied by the clay particles. That's what Brongniart's formula addresses.

Is there any US charity you can turn to for advice. (In the UK Citizens Advice might be worth trying.)

I think the usual form of Brongniart's formula will give you answer. This often uses a value of 2.6 for the density of "typical glaze solids". Which seems close to the density of clay particles. Particle Density https://link.springer.com/referenceworkentry/10.1007/978-1-4020-3995-9_406 Densities of clay minerals range from 2 to 3, but many are near 2.65 g cm PS An old but good ref for t-sig is Super-Refined Terra Sigillata https://digitalfire.com/article/super-refined+terra+sigillata ... but note that it doesn't mention the more modern deflocculants. ... the use of hydrometers has been replaced by weighing an empty and full calibrated syringe in many glaze applications ... it mentions several ways of concentrating thin t-sig, eg As another option, use a crock pot set on medium heat with the lid off. In either case, the rate of drying will depend on the atmospheric humidity and the mount of heat applied. It will take some experimentation to learn the ideal conditions. You may find a cheap crock pot at your local thrift shop. PPS Two threads on the use of Brongniart's formula for glazes "in the bucket". Including references to the formula and a calculator.

What body are you using?

DIY might be an option. 1) Clip on the pix to enlarge 2) 3) 4) Cannot re-find it at the moment but I saw a suggestion that running the wheel 10% slower and using slip instead of water greatly reduced splashing.

Manual for your kiln sitter http://www.fireright.com/docs/kilnsitter/pandk.pdf

First I'll emphasise that I'm just an interested observer not an expert. Second Neil's suggestion of an infinite-switch solution would give you more control during firing, although take more planning and rewiring. Now the real point, IMHO you may have the wrong replacement switch for your kiln. p46 of the A&B series manual shows four different switches (with a fifth mentioned in https://skutt.com/skutt-resources/repairs/switches/). Your first picture identifies the original switch as an A-21, while the second picture suggests that your replacement is a "new-style 3-heat switch". ... from New Style 3-Heat Switch Conversion Instructions in https://skutt.com/skutt-resources/repairs/switches/ It looks like the original A-21 switch is wired with 7 connections, including L1 & L2. ... from https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/IM5-A-and-B-Paragon-Inst-Man-Jan2017.pdf While the 3-heat switches are wired with only 5 connections, which don't seem to include an L2. ... again from New Style 3-Heat Switch Conversion Instructions in https://skutt.com/skutt-resources/repairs/switches/ PS Pin-outs for some other 7-connector switches here:

Well done! Is that before or after firing? If it's after I'm very pleasantly surprised at the absence of visible cracking. Looking at the angles those thorns come out at aren't you going to need a highly multi-part mould to avoid undercuts? (And/or a spectacularly meandering parting line.) Making the problem of achieving a clay build-up for your first plaster pouring even more difficult/fiddly. PS Idle thought. If the wood has burned out cleanly would casting a layer of paperclay inside the bisque be possible? It would strengthen the work -- and allow the original layer to be a thin as the first firing stresses allow.